AGI is often defined as the ability of an intelligent agent to understand or learn intellectual tasks at a human level. A more concrete way to classify AI systems is in terms of their potential impact on the world economy.
Following is a definition of Transformative AI by Ajeya Cotra in her Draft report on AI Timelines:
“Transformative artificial intelligence” (Transformative AI or TAI) is defined as “software” (i.e. a computer program or collection of computer programs) that has at least as profound an impact on the world’s trajectory as the Industrial Revolution did.
How large is an impact “as profound as the Industrial Revolution”? Roughly speaking, over the course of the Industrial Revolution, the rate of growth in gross world product (GWP) went from about ~0.1% per year before 1700 to ~1% per year after 1850, a tenfold acceleration. By analogy, I think of “transformative AI” as software which causes a tenfold acceleration in the rate of growth of the world economy (assuming that it is used everywhere that it would be economically profitable to use it).
Currently, the world economy is growing at ~2-3% per year, so TAI must bring the growth rate to 20%-30% per year if used everywhere it would be profitable to use. This means that if TAI is developed in year Y, the entire world economy would more than double by year Y + 4.